Keyence’s LK-G32 laser displacement sensors, used at the Trémery PSA factory to inspect piston rings, feature heads with small spots 30 microns in diameter (LK-G32) to inspect the scraper and compression rings, and two LK-G82 heads to detect the top ring, says the company. It claims they provide a sampling speed of 50kHz with a repeatability level of 0.05μm for the most accurate models.

As piston rings are reflective parts this affects the measurements, but Keyence says the LK-G range’s correction functions enable stable detection of transparent plastic and metal objects. The Active Balanced Laser control Engine (ABLE) technology detects the surface of a target and adjusts the laser light intensity to the optimum level. The Multiple Reflection Cancel (MRC) algorithm enables elimination of multiple reflections from a metal surface.